Method for separating and recovering lithium and cobalt from positive electrode material of lithium battery

Abstract

The invention provides a method for separating and recovering lithium and cobalt from a positive electrode material of a lithium battery. The method comprises the following: (1) a step of physical disassembly and alkaline leaching; (2) a step of roasting and washing, namely adding sulfate into a black solid material containing lithium cobalt oxide obtained in the step (1) in the weight ratio of the black solid material to the sulfate being 1:(0.8-1.2), mixing, roasting for 2 to 6 hours at a temperature of between 600 and 800 DEG C, cooling, adding a cleaning solution in terms of the ratio of solid to liquid being 1:(3-5) to wash, agitating for 1 to 2 hours at a temperature of between 60 and 80 DEG C and filtering to obtain Li<+>-containing filtrate and filter residue containing lithium and a small amount of cobalt; (3) a step of reducing and acid saluting; and (4) a step of extracting the cobalt to obtain pure Co2<+> solution. By the method, high recovery ratios of the metal lithium and the metal cobalt are achieved, the recovery ratio of the lithium is over 90 percent, the obtained lithium and the obtained cobalt have high purity, the content of the lithium mixed in the cobalt isgreatly reduced, and the purity of the cobalt can reach over 99.5 percent. Therefore, the method has higher economic benefits and social benefits.

Description

technical field [0001] The invention relates to the treatment of non-ferrous metals in waste lithium batteries, in particular to a method for separating and recovering lithium and cobalt from positive electrode materials of lithium batteries. Background technique [0002] Lithium batteries are widely used in electronic products such as notebook computers, mobile phones, digital cameras, and VCDs because of their small size, light weight, high specific energy, long cycle life, and no memory. [0003] my country is the largest producer and consumer of lithium batteries. The life of lithium batteries is generally 3 years, and hundreds of millions of used lithium batteries are eliminated every year. Typical metal contents in spent lithium battery cathode materials are: Co: 22.31%, Li: 3.74%, Ni: 0.4%, Al: 9.78%, and Cu: 7.47%. [0004] Among them, metal cobalt is an important strategic substance. my country's proven cobalt metal content is only 470,000 tons, and most of them ...

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Problems solved by technology

[0009] (1) Extraction method: extracting and separating cobalt and lithium with organic extractants (such as P204 and P507, etc.), there are problems of miscible entrainment and organic extractants that can extract a small amount of lithium at the same time. When preparing cobalt products, it will cause cobalt products. High lithium content greatly affects the quality of cobalt products;

[0010] (2) Chemoselective precipitation method: Precipitating cobalt with ammonium bicarbonate or ammonium oxalate, and then directly calcining or thermally reducing the product. The final cobalt product of this method has a relatively high impurity content, which is due to: (1) Lithium cobaltate material In addition to cobalt and lithium, the leach solution also contains impurities such as aluminum, copper, manganese, and iron; (2) lithium will also have a part of precipitation; and for the recovery of lithium, carbonate precipitation is generally used, but the recovery rate of lithium is generally only About 60%, and the purity is low

[0011] In summary, the current method of separating and recovering cobalt and lithium from waste lithium batteries cannot effectively separate cobalt and lithium, and cobalt products are often mixed with lithium, resulting in a decrease in quality, while the recovery rate of lithium is low

Especially for waste lithium batteries with high lithium content, this problem is more serious

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